Thermotherapy for prevention of perineal pain after vaginal birth: Evaluation of warm compresses and cold packs using a factorial randomized controlled trial

OBJECTIVE: Perineal pain is common after vaginal birth and might affect maternal well-being and mother-infant bonding. We aimed to evaluate the impact of heat or cooling therapy at delivery on postpartum perineal pain. METHODS: This pilot open-label, multicenter 2 × 2 factorial randomized controlled trial included all women without history of vaginal birth, randomly (1:1) assigned to receive heat therapy (HT, warm compresses) or standard care (SC) during pushing, and cooling therapy (CT, cold pack) or SC during immediate postpartum. The primary outcome was the mean of repeated measures of perineal pain intensity (0-10 scale) during the first 24 h. Secondary outcomes included perineal healing, additional analgesic use, childbirth experience, and perineal injuries. Analyses were conducted on a complete-case intention-to-treat basis. RESULTS: From May 2022 to December 2023, 115 women were enrolled and 105 randomized (early termination at 50% of the planned inclusions). Pain intensity was not statistically different between groups: HT versus SC (4.0 ± 2.5 vs. 3.6 ± 2.2, mean difference [95% CI] = 0.43 [-0.56, 1.41]; P = 0.39); CT versus SC (4.3 ± 2.5 vs. 3.4 ± 2.2, mean difference = 0.93 [-0.04, 1.91]; P = 0.06). No statistically significant interaction was observed. HT was not associated with any difference in terms of perineal tear (respectively, with and without HT, for first, second, and third degree tear: 49.0 vs. 54.9%, 37.3 vs. 31.4%, and 5.9 vs. 5.9%; P = 0.94). CONCLUSION: No clear evidence of benefit of heat or cooling therapy for preventing postpartum perineal pain was observed. These non-pharmaceutical methods were generally well accepted by the women and were easy for midwives to implement. Further studies are needed to explore optimal timing, modalities, and target populations. CLINICAL TRIAL REGISTRATION: The PERISAFE protocol was registered in the ClinicalTrial database (2021-03-03, No.NCT04778631). The first participant was recruited in May 2022 (2022-05-16).